In endoscopic vessel harvesting (EVH) surgical procedures, a long slender surgical instrument may be introduced into a tunnel next to a target vessel (e.g., a saphenous vein or a radial artery) in a patient, and advanced along the vessel to dissect the vessel away from adjacent tissue and to sever side-branch vessels along the course of the target vessel.
EVH devices for performing vessel harvesting may include a jaw assembly with a heating element. During use, the jaw assembly is used to grasp a vessel or tissue, and the heating element is activated to cut and seal the vessel or tissue. Sometimes, during use of such an EVH device, the heating element may be activated for too long of a duration, thereby causing the device to overheat. Also, the jaw assembly may be closed and the heating element activated without grasping tissue between the jaws. This may cause the jaw assembly to overheat more quickly because of the absence of tissue between the jaws to absorb the thermal energy from the heating element. The resulting high temperature may cause material and mechanism failures, such as degradation of jaw members, melting of mechanical linkages, destruction of electrical circuit, etc.
Also, existing EVH devices do not have any mechanism for controlling the delivery of energy to tissue in a manner that ensures that tissue is transected quickly while simultaneously preventing overheating of the tissue.